Cinar, Hediye N. et al. (2009) International Worm Meeting "Cell Vacuolation, a Manifestation of Vibrio cholerae Hemolysin in Caenorhabditis elegans Intestine."

Yildiz, Fitnat, Bilecen, Kivanc, Kothary, Mahendra, McCardell, Barbara, Datta, Atin, Tall, Ben D., Sprando, Robert, Cinar, Hediye N.

[International Worm Meeting, 2009]

Vibrio cholerae (VC), a natural dweller of aquatic ecosystem, causes acute gastroenteritis in humans, using virulence factors such as cholera toxin (CT) and toxin co-regulated pili (TCP). Vibrio cholerae O1 and O139 serogroups are associated with cholerae epidemics, while non-O1 non O-139 strains, which mostly lack CT and TCP, and vaccine strains with deleted CT and TCP loci are also capable of causing diseases such as diarrhea, soft tissue infections, sepsis, and inflammatory enterocolitis in humans in a sporadic fashion through mechanisms that are currently unclear. VC causes lethal infection in Caenorhabditis elegans via a CT / TCP independent process providing an excellent model to determine the roles of other virulence factors in pathogenesis (1, 2). We found that hemolysin (hlyA) deletion mutants showed attenuated killing in C. elegans which is an effect that can be complemented by the presence of an intact hlyA locus (3). Furthermore, O1 classical strains, which produce less hemolysin than O1 El tor strains, showed milder lethality and reduced developmental delay. It has been reported that VC hemolysin causes extensive vacuolization and lysis in cultured cells. We examined worms fed with either wild type or hlyA deletion mutants of VC for intestinal pathologies. Forty-six percent of the worms exposed to wild type VC exhibited intestinal vacuoles while none one of the worms fed an hlyA deletion mutant showed this defect after 48-hour exposure. Other intestinal pathologies such as distention of the intestinal lumen and intestinal cell shrinkage were observed in both hly+ and hly- conditions, although the defects were more severe in hly+ conditions. Intestinal lumen distention and cell shrinkage preceded vacuolization suggesting that intestinal colonization of the bacteria may be necessary for vacuole formation. Hemolysin A is a pore forming exotoxin whose role in VC pathogenesis is not fully understood. Further studies in C. elegans infection model will contribute to a greater understanding of the role of hemolysin virulence in the pathogenesis of cholera. (1) Vaitkevicius K. et al. PNAS, 103 (2006) 9280-9285 (2) Cinar HN. et al. 16 th International C. elegans Meeting, 2007 (3) Cinar HN. et al. Aging Stress and Pathogenesis Meeting, 2008.